Climate change is lengthening growing seasons: How it's impacting every state
Climate change is lengthening growing seasons: How it's impacting every state
Hobby gardeners and professional farmers have long relied on weather predictions from farmers' almanacs and other sources to guide how they start seeds and prepare for the upcoming season. Climate change, however, has altered the predictability of each region's final spring frost and the first frost in fall, shifting their growing seasons.
Stacker examined how the average length of growing seasons has changed across every state between 1895 and 2020, citing data from the National Centers for Environmental Information and packaged by the Environmental Protection Agency. Please note data was not available for Alaska and Hawaii.
Additional data on change in the average timing of first and last frosts is also included. However, those two measures may not add up to the exact difference in growing season length because of the statistical methods used to calculate the average dates and durations.
Across the U.S., the 2020 average growing season was 13 days longer than the long-term 1895-2020 average would have suggested, putting those almanacs off by whole weeks.
Those long-term trends can hide the season-to-season irregularity climate change has also fueled. Bulbs may emerge as a first sign of spring only to lose their luster in a late-spring snap freeze. Fruit trees can have their growth stunted when a warm spring begins and is disrupted by a frost.
Shifting growing seasons affect more than people's backyards. In 2021, American farms contributed over $160 billion to the U.S.'s GDP, about 0.7% of the total. Irregular seasons can have especially pronounced effects on smaller family farms.
On paper, a longer growing season might seem like more days to grow food—a promising possibility. But it's not that simple. Plants grow and develop differently: Warm-weather plants like tomatoes and peppers may enjoy the extended summer, but cool-season crops like spinach and cauliflower may face early bolting if the season is fueled by hotter days. Longer seasons also support organisms farmers don't want—like weeds, pests, and invasive species.
The shifting patterns have enabled new regions to become hubs for crops they haven't traditionally grown, but it can also mean farmers have to rethink their livelihoods.
Western vs. Eastern US
The average growing season length is up across the board in the U.S. The analysis divides the two regions with a straight north-south line following the eastern side of the Texas panhandle.
Beyond temperatures, climate change has also shifted precipitation patterns. The West has seen elongated droughts, causing farmers to rely on aquifers for irrigation, though they are reaching alarmingly low levels.
In other regions, extreme levels of rain can promote crop diseases, lowering yields and affecting groceries beyond just the produce aisle.
Read on to see how your state's growing season has changed over the past 130 years.
Alabama
- Change in length of growing season: 1.9 fewer days
- Change in timing of first fall frost: 1.1 days earlier
- Change in timing of last spring frost: 1.0 days later
Arizona
- Change in length of growing season: 49.8 more days
- Change in timing of first fall frost: 18.2 days later
- Change in timing of last spring frost: 29.3 days earlier
Arkansas
- Change in length of growing season: 14.4 more days
- Change in timing of first fall frost: 9.0 days later
- Change in timing of last spring frost: 5.8 days earlier
California
- Change in length of growing season: 50.9 more days
- Change in timing of first fall frost: 18.5 days later
- Change in timing of last spring frost: 31.0 days earlier
Colorado
- Change in length of growing season: 11.2 more days
- Change in timing of first fall frost: 4.8 days later
- Change in timing of last spring frost: 5.5 days earlier
Connecticut
- Change in length of growing season: 27.7 more days
- Change in timing of first fall frost: 13.4 days later
- Change in timing of last spring frost: 13.8 days earlier
Delaware
- Change in length of growing season: 27.5 more days
- Change in timing of first fall frost: 7.9 days later
- Change in timing of last spring frost: 18.5 days earlier
Florida
- Change in length of growing season: 25.6 more days
- Change in timing of first fall frost: 14.5 days later
- Change in timing of last spring frost: 10.9 days earlier
Georgia
- Change in length of growing season: 10.9 fewer days
- Change in timing of first fall frost: 2.9 days earlier
- Change in timing of last spring frost: 8.3 days later
Iowa
- Change in length of growing season: 11.1 more days
- Change in timing of first fall frost: 4.3 days later
- Change in timing of last spring frost: 6.8 days earlier
Idaho
- Change in length of growing season: 25.9 more days
- Change in timing of first fall frost: 11.3 days later
- Change in timing of last spring frost: 4.5 days earlier
Illinois
- Change in length of growing season: 8.6 more days
- Change in timing of first fall frost: 2.3 days later
- Change in timing of last spring frost: 7.0 days earlier
Indiana
- Change in length of growing season: 12.7 more days
- Change in timing of first fall frost: 4.4 days later
- Change in timing of last spring frost: 7.9 days earlier
Kansas
- Change in length of growing season: 14.8 more days
- Change in timing of first fall frost: 6.1 days later
- Change in timing of last spring frost: 4.3 days earlier
Kentucky
- Change in length of growing season: 6.8 more days
- Change in timing of first fall frost: 5.1 days later
- Change in timing of last spring frost: 2.2 days earlier
Louisiana
- Change in length of growing season: 20.2 more days
- Change in timing of first fall frost: 11.4 days later
- Change in timing of last spring frost: 8.2 days earlier
Massachusetts
- Change in length of growing season: 11.5 more days
- Change in timing of first fall frost: 7.3 days later
- Change in timing of last spring frost: 3.5 days earlier
Maryland
- Change in length of growing season: 23.3 more days
- Change in timing of first fall frost: 14.2 days later
- Change in timing of last spring frost: 12.0 days earlier
Maine
- Change in length of growing season: 15.1 more days
- Change in timing of first fall frost: 7.0 days later
- Change in timing of last spring frost: 8.4 days earlier
Michigan
- Change in length of growing season: 13.6 more days
- Change in timing of first fall frost: 8.0 days later
- Change in timing of last spring frost: 5.8 days earlier
Minnesota
- Change in length of growing season: 19.6 more days
- Change in timing of first fall frost: 7.2 days later
- Change in timing of last spring frost: 11.1 days earlier
Missouri
- Change in length of growing season: 11.0 more days
- Change in timing of first fall frost: 5.0 days later
- Change in timing of last spring frost: 6.4 days earlier
Mississippi
- Change in length of growing season: 0.7 more days
- Change in timing of first fall frost: 1.0 days later
- Change in timing of last spring frost: 0.7 days later
Montana
- Change in length of growing season: 12.7 more days
- Change in timing of first fall frost: 7.9 days later
- Change in timing of last spring frost: 5.5 days earlier
North Carolina
- Change in length of growing season: 6.4 more days
- Change in timing of first fall frost: 3.8 days later
- Change in timing of last spring frost: 3.4 days earlier
North Dakota
- Change in length of growing season: 31.0 more days
- Change in timing of first fall frost: 16.2 days later
- Change in timing of last spring frost: 15.8 days earlier
Nebraska
- Change in length of growing season: 9.4 more days
- Change in timing of first fall frost: 3.9 days later
- Change in timing of last spring frost: 3.9 days earlier
New Hampshire
- Change in length of growing season: 21.8 more days
- Change in timing of first fall frost: 12.0 days later
- Change in timing of last spring frost: 8.6 days earlier
New Jersey
- Change in length of growing season: 16.8 more days
- Change in timing of first fall frost: 10.8 days later
- Change in timing of last spring frost: 6.0 days earlier
New Mexico
- Change in length of growing season: 13.3 more days
- Change in timing of first fall frost: 6.3 days later
- Change in timing of last spring frost: 8.0 days earlier
Nevada
- Change in length of growing season: 12.0 more days
- Change in timing of first fall frost: 7.0 days later
- Change in timing of last spring frost: 2.9 days earlier
New York
- Change in length of growing season: 11.5 more days
- Change in timing of first fall frost: 8.0 days later
- Change in timing of last spring frost: 4.6 days earlier
Ohio
- Change in length of growing season: 16.3 more days
- Change in timing of first fall frost: 10.2 days later
- Change in timing of last spring frost: 8.5 days earlier
Oklahoma
- Change in length of growing season: 4.9 more days
- Change in timing of first fall frost: 4.0 days later
- Change in timing of last spring frost: 1.4 days earlier
Oregon
- Change in length of growing season: 26.6 more days
- Change in timing of first fall frost: 12.2 days later
- Change in timing of last spring frost: 16.1 days earlier
Pennsylvania
- Change in length of growing season: 19.6 more days
- Change in timing of first fall frost: 15.2 days later
- Change in timing of last spring frost: 6.0 days earlier
Rhode Island
- Change in length of growing season: 11.4 more days
- Change in timing of first fall frost: 7.0 days later
- Change in timing of last spring frost: 2.8 days earlier
South Carolina
- Change in length of growing season: 5.0 more days
- Change in timing of first fall frost: 2.3 days later
- Change in timing of last spring frost: 1.8 days earlier
South Dakota
- Change in length of growing season: 17.5 more days
- Change in timing of first fall frost: 7.4 days later
- Change in timing of last spring frost: 9.1 days earlier
Tennesee
- Change in length of growing season: 3.9 more days
- Change in timing of first fall frost: 4.8 days later
- Change in timing of last spring frost: 0.7 days earlier
Texas
- Change in length of growing season: 8.3 more days
- Change in timing of first fall frost: 1.9 days later
- Change in timing of last spring frost: 5.6 days earlier
Utah
- Change in length of growing season: 33.0 more days
- Change in timing of first fall frost: 13.2 days later
- Change in timing of last spring frost: 19.0 days earlier
Virginia
- Change in length of growing season: 13.6 more days
- Change in timing of first fall frost: 8.8 days later
- Change in timing of last spring frost: 4.1 days earlier
Vermont
- Change in length of growing season: 11.9 more days
- Change in timing of first fall frost: 7.9 days later
- Change in timing of last spring frost: 4.0 days earlier
Washington
- Change in length of growing season: 35.0 more days
- Change in timing of first fall frost: 14.6 days later
- Change in timing of last spring frost: 22.9 days earlier
Wisconsin
- Change in length of growing season: 15.7 more days
- Change in timing of first fall frost: 6.8 days later
- Change in timing of last spring frost: 8.2 days earlier
West Virginia
- Change in length of growing season: 6.6 more days
- Change in timing of first fall frost: 8.2 days later
- Change in timing of last spring frost: 0.6 days later
Wyoming
- Change in length of growing season: 34.4 more days
- Change in timing of first fall frost: 13.8 days later
- Change in timing of last spring frost: 21.0 days earlier
Story editing by Jeff Inglis. Copy editing by Kristen Wegrzyn. Photo selection by Ania Antecka.
